The insights into how tattoo pigments stays under the skin and only dissipates and gets blurry over many years is surprisingly recent. In 2018, a team of immunologists from the Centre d'Immunologie de Marseille-Luminy in France led by Anna Baraska tested a new genetically modified mouse model that enables exploration of the human CD64 gene for immunoglobulin G receptors via exposure to diphtheria. Gene targeted mice are mice that have specific mutations to inactivate or modify a specific gene, which enables scientists to explore changes in the gene activity compared to control mice without the change. Diphtheria is a bacterial disease that affects mucous membranes of the nose and throat with a mortality rate of 5-10% of cases, particularly among young children.

Mice were tattooed on ears and tails and compared for levels of cell types. Ears had four times more melanocytes, the precursors to macrophages, than tails. They scraped the mice with diphtheria to cause tissue damage and determine how the cells appeared after healing. They found the green pigment of tattoos remained at the highest density where macrophages were concentrated and concluded that macrophages eat pigment to remove it from circulation. However, during normal cell death and replacement, cells cast off pigment that is re-engulfed by incoming cells of similar type. They witnessed this capture-release-recapture over a 90 day period and hypothesized this process is responsible for holding pigment in place, rather than removing it from the skin, as we might expect the immune system to do.

To ensure this wasn’t simply a by-product of exposure to diphtheria, they grafted the tattooed  tail skin of a gene-targeted mouse onto an albino mouse and watched the progression of healing. The tattoo remained over 6 weeks, and the cells were host cells, indicating that the host mouse’s macrophage cells were engulfing the pigment as the preceding cells died, exactly as in the original tattooed mouse.

A follow-up study led by Helen Strandt of the University of Salzburg in Austria with members of the Marseilles group and using the same methods examined a type of structural cell called fibroblasts because they form the connective tissue of skin.  They found that fibroblasts hold pigment but occur at a lower rate than macrophage cells containing pigment. They speculate that fibroblasts are active taking up pigments during the initial administration of the tattoo when the collagen is damaged and continue to maintain pigment but at a lower rate than macrophages.

A 2022 study published in Frontiers in Immunology by a group in France specializing in the chemistry and biology of metals examined the influence of specific pigments on macrophages. Metals are at the base of several pigments, so this study involved investigation of three cobalt (purple) or cobalt alloy (blue and green) pigments and one zinc (white) pigment. The test was conducted directly on mouse macrophage cell lines and exposed to various concentrations of pigment. Pigments came from Kama Pigments and Tokyo Pigment. They compared acute exposure within the first 24 hours to a 3-day exposure recovery period. All pigments triggered macrophages to eat them, but the activity varied by pigment, and all pigments induced a slight, transitory tumor necrosis factor secretion. By contrast, blue produced a short and sustained increase in interleukin 6 secretion.

The most recent study of the role of macrophages in holding tattoo pigment in place also examined the inflammatory and toxic roles of the inks in place. The authors, a group from Aachen, Germany led by Cheng Lin, used full-thickness 3D skin models designed to study wound healing. They found that macrophages are very efficient at taking up pigment (Sailor Jerry black), that basic black has no inflammatory or toxic effects, and that monocytes (macrophage precursors), which are particularly sensitive to absorbing pigment, and lymphocytes and granulocytes may be responsible for carrying small amounts of pigment away to the lymph nodes and internal organs.

We have a new article out in Pacific Journal of Health that explores a case study of tatau. We collected cortisol throughout multiple days for a man getting a Samoan pe'a tattoo. This is the first documentation of the physiological response to traditional tattooing that we know of. Read the full open access text here.

Michelle Myles is a tattoo artist originally from St. Louis but who has been tattooing on New York's Lower East Side since before it became legal again in NYC in 1997. She was the owner of Fun City (I remember Fun City II as the only visible tattoo shop in the Village when it was illegal, run by Jonathan Shaw). Later, she started Daredevil Tattoo with her partner Brad Fink on Ludlow Street, which at the time had a few hole in the wall bars that featured occasional bands, the all-ages punk club ABC NoRio, and heroin dealers. Then they moved down to an even shadier part of LES at Division St. and Canal near the East Broadway stop on the F train, Seward Park, and the old Jewish Daily Forward newspaper building. Today that neighborhood is bougie and much safer, without any obvious heroin dealing going on.

I took a tour of the tattoo history of the Bowery with Michelle, and she told me that she tattooed a bunch of the dealers, who then protected her in the neighborhood. Michelle is a registered NYC tour guide, and her husband is a tattoo collector. They have a Tattoo Museum featuring an Edison electric pen, which was modified to become the first electric tattoo machine by Samuel O'Reilly. O'Reilly is originally from England but set up shop in NYC in the early 20th century, and they have one of his machines, as well as hundreds of sheets of flash from celebrated early and mid-twentieth century artists from New York. I arrived late because of time zone issues when booking, but we hit it off, so she squeezed in the full tour. It helps that I used to be a tour guide for the Lower Eastside Tenement Museum, so I already knew the history of the social and architectural histories of the neighborhood and  could skip to the tattooing.

​Michelle and I are the same age, both came from the Midwest to New York around the same time (she came a few years before me), and did our times in the music scene before settling down into history and intellectual pursuits, so we had a grand time talking shop as she took me to the Bowery and showed me where Charlie Wagner had his shop, where Lew the Jew had his shop, where Apache Harry had his shop (also Jewish fyi), and the list goes on. These shops were in the backs of saloons, barber shops, and dentists and only occasionally were stand-alone businesses. She talked a lot about the role of the elevated train over the Bowery making it a dingy place, which I recall from Michael McCabe's book from the 1980s, New York City Tattoo.

Tattooing existed in New York and other cities before it became electrified, but it certainly took off as an industry with Edison's and O'Reilly's inventions. As I learned from a recent webinar by Chuck Eldridge of Tattoo Archive, O'Reilly was one of several people tinkering with Edison's patent and simply the first to patent a device of his own. Tattooing has been practiced without electricity for thousands of years, but in the 19th century, numerous inventors were toying with ways to electrify tattooing. The now well-established lore is that after Thomas Edison invented the electric pen to automate filling out forms in triplicate, a number of tinkerers rushed to refine it into a tattoo machine. The first successful patent was given to Samuel O’Reilly.

​What is different about the electric tattoo machine? Electric machine tattooing is different simply in the mechanization that speeds up certain aspects of tattooing. The principle of the electric tattoo machine is that something is moving the needle back and forth at a rapid pace. Tattoo machines can be made from anything with a moving part, which is why so many prison tattoo machines are made from such devices as CD players or electric razors. In the electric tradition, the whole machine is held in the artist’s drawing handing and operated with a foot or finger switch. Non-electric styles achieve the same movement by hand. In the Pacific, one hand holds the tattooing comb (an ‘au in Samoan), and the other hand taps the pattern in with a rod (a sausau in Samoan). In Japan tebori tattooing, the pigment is poked in from the end of a wooden or metal stick of various sizes (called sashibo or nomi). With stick and poke, one administers tattoos by hand with a simple needle or tattoo needle bundle (tattoo needles come pre-made and easily obtainable via mail-order) hafted to a pencil or chopstick.

Paul “Junior” Sulu’ape pounds on his thighs to work the feeling back into them. He and his brothers Peter and Ata are sixth generation tufuga tå tatau, and Paul spends anywhere from 6-12 hours a day, six days a week sitting cross-legged on the floor of a fale giving traditional Samoan tatau in the outdoor Cultural Arts Center in downtown Apia on the island of ‘Upolu, Samoa. As a titled master craftsman, Paul’s proper name is Su’a Sulu’ape Paulo III. They are of the Su’a guild of Samoan tattooists, and the Sulu’ape family have inherited the Su’a title through family ties. Paul’s father is pule in charge of titles and land for the family. Those his father has trained in traditional tatau can earn the Sulu’ape title. Those especially trusted can earn the Su’a title. Paul and his brothers earn them automatically through training as tattooists and being sons of Su’a Sulu’ape Petelo Alaiva’a.

As most experienced tufuga working today at the Cultural Arts Center, Paul serves a head matai or chief for the samaga ceremony that takes place when tatau are completed. His legs are stretched out under a leaf mat as he massages the stiffness out of his legs, as it is inappropriate to point the soles of bare feet at others. Paul grew up in a tattoo family. His grandfather Paulo I passed before he was born, but his uncle Paulo II, father Alaiva’a, uncle Petelo, uncle Lafaele, and brother Peter were all hand tap tattooists in the Samoan tradition. However, culture is not static. Much as tatau has been uniquely maintained in Samoa through the missionary and colonial periods, accommodations have also been made to modernity. To ensure compliance with global sanitary standards. The ‘au or hammer has been redesigned with material that can be sterilized in an autoclave. Paul’s father Alaiva’a introduced these changes in the 1990s. Paul began tattooing with electric machines and picked up hand tapping from watching his father and brother. He has never used the prior tools made with boar’s tusk, which purportedly felt slightly different to use and were more painful to feel. Paul grew up in the 1980s and 1990s and spent as much time in chairs as his father and grandfather spent sitting cross-legged. While the ~25 hours required to complete a pe’a seems almost intolerably painful, the hours spent leaning over body after body tapping in Samoan designs seems even harder. Paul has dedicated himself to preserving his family and cultural heritage but needs acupuncture even as a young man in his twenties for the pain and discomfort of its hardships.

I began working with the Sulu’apes to study the biology and culture of Samoan tatau but was surprised by such additional aspects of cultural embodiment. Tattooing is the perfect topic for anthropological study, given the discipline’s varied foci on culture, biology, linguistics, and archaeology.